1. Field of the Invention
The present invention relates is directed to an eye direction detecting apparatus that is provided in a single lens reflex camera, and a view finder of a single lens reflex camera having a diopter adjusting device.
2. Description of Related Art
A known eye direction detecting apparatus (referred to as an eye detector) is disclosed, for example, in U.S. Pat. No. 5,036,347. The known eye detector in a single lens reflex camera is provided in the vicinity of a pentagonal prism, so that a bundle of rays emitted from a light source, such as a light emitting diode (LED), is made incident upon a photographer's eye through an eyepiece of the view finder. Light reflected by the photographer's eye is then converged and received by a light receiving element, such as a CCD sensor, whose output is electrically processed to detect the eye direction. In single lens reflex cameras that employ an eye direction detecting apparatus as described above, a significant amount of space is required for the eye direction detecting apparatus, resulting in an excessively large camera.
A view finder of a single lens reflex camera having a diopter adjusting device, in addition to an eye direction detector, is also known. In a known view finder, for example, when the eyepiece closest to a photographer's eye is moved in the optical axis direction to adjust the diopter, the incident angle of the bundle of eye direction detecting rays incident upon the photographer's eye will vary. Consequently, an optical positional relationship between the eye and the light receiving element of the eye detector will vary, resulting in an inaccurate detection of the eye direction.